ZIP code 21784: Eldersburg, MD
ZIP code 21784 is in Eldersburg (75% of residents) and Sykesville (11%), in Carroll County (94%) and Howard County (5.6%), Maryland. 14% of its residents live outside city limits. It is in Maryland's 2nd congressional district (79%) and Maryland's 3rd congressional district (21%). Its state senate districts are State Senate District 5 (94%) and State Senate District 9 (5.6%); its state house districts are State Legislative District 5 (94%) and State Legislative Subdistrict 9A (5.6%).
See it on the mapAll of Maryland
City and county
| City or town | Share of ZIP residents |
|---|---|
| Eldersburg | 75% |
| Sykesville | 11% |
| County | Share of ZIP residents |
|---|---|
| Carroll County | 94% |
| Howard County | 5.6% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| District 5, Freedom | 69% |
| District 14, Berrett | 24% |
| District 3, West Friendship | 4.7% |
| District 4, Woolerys | 1.1% |
| District 4, Lisbon | 0.9% |
| District 9, Franklin | 0.1% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Maryland's 2nd congressional district (MD-02) | 79% |
| Maryland's 3rd congressional district (MD-03) | 21% |
This ZIP is split between districts. A mailing address in it could be in either; the map or locate_point gives the district for an exact address.
Elected officials
| Office | Member | Contact | Share of residents |
|---|---|---|---|
| U.S. Representative (MD-02) | Johnny Olszewski, Jr. (D) | 202-225-3061 | 79% |
| U.S. Representative (MD-03) | Sarah Elfreth (D) | 202-225-4016 | 21% |
| U.S. Senator | Angela D. Alsobrooks (D) | 202-224-4524 · contact form | statewide |
| U.S. Senator | Chris Van Hollen (D) | 202-224-4654 · contact form | statewide |
| State Senator (State Senate District 5) | Justin Ready (R) | 94% | |
| State Senator (State Senate District 9) | Katie Hester (Democratic) | 5.6% | |
| Delegate (State Legislative District 5) | April Rose (R) | 94% | |
| Delegate (State Legislative District 5) | Chris Tomlinson (R) | 94% | |
| Delegate (State Legislative District 5) | Christopher Bouchat (R) | 94% | |
| Delegate (State Legislative Subdistrict 9A) | Chao Wu (Democratic) | 5.6% | |
| Delegate (State Legislative Subdistrict 9A) | Natalie Ziegler (Democratic) | 5.6% |
Officials serving now (members of Congress until January 3, 2027). Sources: State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).
Local government
- Eldersburg laws: search for the Eldersburg, Maryland code of ordinances
- Sykesville website: http://www.townofsykesville.org/
- Sykesville laws: search for the Sykesville, Maryland code of ordinances
- Carroll County website: https://www.carrollcountymd.gov/
- Carroll County laws: search for the Carroll County, Maryland code of ordinances
- Howard County website: https://www.howardcountymd.gov/
- Howard County laws: search for the Howard County, Maryland code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 5 | 94% |
| State Senate District 9 | 5.6% |
| State house district | Share of ZIP residents |
|---|---|
| State Legislative District 5 | 94% |
| State Legislative Subdistrict 9A | 5.6% |
Voting precincts
15 voting precincts overlap ZIP 21784. Map them, with each precinct's share of the ZIP's residents.
Get this in your AI agent
Your agent can get these cities, counties, districts and precincts with their shares, and their GeoJSON boundaries, from Boundary Atlas. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:
related_geographies(id="us:zcta:21784")
ZIP 21784 here is the Census Bureau's ZIP Code Tabulation Area, which approximates the USPS ZIP Code; PO-box-only ZIPs have none. Districts are the maps in force for the November 3, 2026 election.